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Wednesday, January 6, 2016

REDUX - RV Repair - replacing gaskets on rooftop Duo Therm Penguin Air Conditioners

In the last week or so, I have had two people ask me about replacing the gaskets in the rooftop air conditioners on our motorhome.   Since it's the boring winter months, and we are not travelling yet, I thought I would do some repeats of my most-read blog posts on RV repairs.  This one had over 1,580 views when I first posted it. 

RV Repair - replacing gaskets on rooftop Duo Therm Penguin Air Conditioners

As many of you know, our motorhome is now 18 years old.  Yup.. it's old enough to vote! 

Routine maintenance has kept it up in tip top shape, with 99% of it being done by ourselves.  The few things we have had other people do, we realize we could have done ourselves with a bit more information.  And also I think we would have done a better job, with more attention to details, and cost us much less in labor and parts. 

So I try to take pics of the things we do ... step by step... and hope they will help someone else to do the job themselves too.  (rather than paying someone $100 an hour to do it)  

We noticed a bit of water leaking down onto our bed from the back rooftop air conditioner.  This has happened once before on the front unit, and we learned a trick to remove the bottom plastic housing and tighten down on the three big bolts... compressing the gasket a bit more.

This time, we realized the gasket was almost flat and not doing it's job on the back unit.  So we picked up two new gaskets to replace both of them when we had time.   Gaskets are generally available at most RV dealers.  We bought ours at Merz RV in Fond du Lac and they were pricier than what we found online.  We paid $35 each, but Steve wanted them NOW.... and not wait to order them I guess. Gotta keep the local RV dealers in business too I guess.

Here is one I found online so you can get an idea of what I am talking about.  Yup, it is just a square shape of closed cell foam rubber that is sticky on one side.  We didn't use the leveling pads, perhaps those are for some fifth wheels I see with sloped rooftops where the AC unit is attached....  I think most RV's use the same gasket, as the hole in the rooftop is pretty universal in size.

You know Steve... NOW was the time!  In all fairness, we are due for some more rain this week and prefer to not have any more water on the bed!   As it was, the drips hit our LED tv we lay flat on the bed during travel, and we now have a red streaky line vertically on the screen, probably permanent.  Sigh.

I took step by step pics of the process. We have two Duo Therm Penguin rooftop air conditioners but I only documented changing out one of the gaskets.  They both were replaced the same way.

First .... UNPLUG your rig from any power source!   Then assemble all of the needed tools (aluminum sticky tape, oscillating power tool, permanent marking pen, rags & acetone, and a ladder... with an assortment of various screwdrivers, ratchets, sockets and fun stuff like a camera to take pics)

 We looked up inside and saw why our gasket was leaking:

this part might be easier if done with TWO people, but Steve is strong.... 

I would suggest here that before you remove the old gasket material, 
to make some marks with a permanent marker. 
This will show you exactly where the new gasket needs to be attached... 
so it will perfectly line up with the rooftop hole.

If you had marked with a permanent pen here, 
you wouldn't have to guess where the gasket needs to be applied. 

Again, this next part would work better 
with two people lifting, 
and a third person on the inside 
to eyeball how it's lining up 
with the hole in the roof.

You could use duct tape here, but Steve had some of this on hand too

now to take care of a couple air leaks that were never done from the factory either.

We feel the air will flow better by plugging up the leaks
that should have been plugged from the time it was built.


  1. Your excellent narrative and pix makes me want to go out and buy such an A/C unit. Do they still sell them? Seriously, some people Alfa owners put a 3rd air conditioner on the roof, because they are so averse to warmth that the 2 that come with the coach aren't enough for them! Are you going traveling this winter? If so, we hope to see you.

  2. We have been putting off replacing our air conditioner because I can not afford to pay the local mechanic to right now. Watching this blog and looking closely at the pictures made me realize that I can definitely do it myself. Thank you for taking all those pictures and for detailing the steps in order so perfectly. Will keep you posted.

    Randall Rogers @ R J Heating and Cooling


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